Microcapsule powder

ABSTRACT

A process for making hydrophobicized powders of micro- and/or nanocapsules involving the steps of: (a) providing an aqueous polymer solution containing at least one active ingredient and at least one hydrophilic polymer; (b) providing an oil component heated to a temperature above a gel point of the aqueous polymer solution; (c) dispersing (a) in (b) in the presence of a water-in-oil emulsifier to form a dispersion; (d) cooling the dispersion to a temperature below the gel point of the aqueous polymer solution to form micro- and/or nanocapsules containing the active ingredient encapsulated therein; (e) harvesting the micro- and/or nanocapsules from the dispersion; and (f) contacting the micro- and/or nanocapsules with an oil-absorbing auxiliary ingredient.

BACKGROUND OF THE INVENTION

This application is a 371 of PCT/EP01/10765 filed Sep. 18, 2001.

This invention relates generally to the encapsulation of activesubstances and, more particularly, to hydrophobicized powders consistingof micro- and/or nanocansules, to a process for their production and totheir use in cosmetic and pharmaceutical preparations.

“Microcapsules” are understood to be spherical aggregates with adiameter of about 1 to about 5,000 μm and “nanocapsules” similaraggregates with a diameter below 1 μm which contain at least one solidor liquid core surrounded by at least one continuous membrane. Moreprecisely, they are finely dispersed liquid or solid phases coated withfilm-forming polymers, in the production of which the polymers aredeposited onto the material to be encapsulated after emulsification andcoacervation or interfacial polymerization. In another process, liquidactive principles are absorbed in a matrix (“microsponge”) which, asmicroparticles, may be additionally coated with film-forming polymers.Transitions between micro- or nanoparticles in which substances areencapsulated in a membrane (reservoir system) and micro- ornanoparticles in which the active substances are dispersed or dissolvedin the carrier matrix (matrix system) arise out of the particularproduction process. Besides single-core microcapsules, there are alsomultiple-core aggregates, also known as microspheres, which contain twoor more cores distributed in the continuous membrane material. Inaddition, single-core or multiple-core microcapsules may be surroundedby an additional second, third etc. membrane. The membrane may consistof natural, semisynthetic or synthetic materials. Natural membranematerials are, for example, gum arabic, agar agar, agarose,maltodextrins, alginic acid and salts thereof, for example sodium orcalcium alginate, fats and fatty acids, cetyl alcohol, collagen,chitosan, lecithins, gelatin, albumin, shellac, polysaccharides, such asstarch or dextran, polypeptides, protein hydrolyzates, sucrose andwaxes. Semisynthetic membrane materials are inter alia chemicallymodified celluloses, more particularly cellulose esters and ethers, forexample cellulose acetate, ethyl cellulose, hydroxypropyl cellulose,hydroxypropyl methyl cellulose and carboxymethyl cellulose, and starchderivatives, more particularly starch ethers and esters. Syntheticmembrane materials are, for example, polymers, such as polyacrylates,polyamides, polyvinyl alcohol or polyvinyl pyrrolidone.

Examples of known microcapsules are the following commercial products(the membrane material is shown in brackets) Hallcrest Microcapsules(gelatin, gum arabic), Coletica Thalaspheres (maritime collagen),Lipotec Millicapseln (alginic acid, agar agar), Induchem Unispheres(lactose, microcrystalline cellulose, hydroxypropylmethyl cellulose),Unicerin C30 (lactose, microcrystalline cellulose, hydroxypropylmethylcellulose), Kobo Glycospheres (modified starch, fatty acid esters,phospholipids), Softspheres (modified agar agar) and Kuhs ProbiolNanospheres (phospholipids).

Reference is also made in this connection to German patent applicationDE 19712978 A1 (Henkel) which describes chitosan microspheres obtainedby mixing chitosans or chitosan derivatives with oil components andintroducing the resulting mixtures into alkalized surfactant solutions.In addition, the use of chitosan as an encapsulating material fortocopherol is known from German patent application DE 19756452 A1(Henkel). Patent Application EP 99 122 906 relates to microcapsules withmean diameters of 0.1 to 500, preferably 25 to 250 and more particularly50 to 100 μm which consist of a membrane material of starch andchitosans.

The micro- and nanocapsules produced in different ways may then beconverted into a powder-form end product by drying in the form offreeze-drying or fluidized-bed drying or by the removal of water (FR2775441 B1 and EP 99 122 906). In many cases, however, furtherprocessing such as this involves complicated, expensive andtime-consuming processes and often leads to premature destruction of themicro- and nanocapsules. Since the microcapsules have hydrophilicsurface properties, they are often difficult to incorporate inlipophilic preparations.

So-called dispersion aids (colloidal silicon), which contribute towardsoptimizing the flowability of the powders, are only used after thepowders have been isolated. An advantage of similar formulations used incosmetics is the regulation of fat-absorbing as opposed to drying-outproperties (U.S. Pat. No. 5,948,417). U.S. Pat. No. 5,356,617 describeshow the unsatisfactory processing of hydrophilic pigments can beimproved by the production of microparticles from organic polymer,inorganic pigments and a binder. Even oily substances and lipophiliccarriers can be converted for better processing into powders which arethen readily incorporated in cosmetic preparations (EP 0 659 403 andU.S. Pat. No. 4,164,563). However, the use of micro- and/or nanocapsulesraises greater processing problems.

The active principles are released from the microcapsules by mechanical,thermal, chemical or enzymatic destruction of the membrane or bydiffusion, normally during the use of the preparations containing themicrocapsules. Disadvantages in this regard are that the microcapsulesdo not allow controlled release of the active principles from theirinterior at all or only to an inadequate extent and that the capsuleslack stability in the presence of surfactants, especially anionicsurfactants, salts or mechanical loads.

Accordingly, the problem addressed by the present invention was toprovide a stable powder-form formulation consisting of hydrophilicallyencapsulated active substances and auxiliaries which would be easy toincorporate in water-free formulations. The powder would be produced bysimple, economical processes. In addition, release behavior would beable to be controlled and the formulation would be guaranteed a longstorage life.

DESCRIPTION OF THE INVENTION

The present invention relates to hydrophobicized powders consisting ofmicro- and/or nanocapsules obtainable by

-   (a) dispersing an aqueous solution of at least one polymer in an oil    in the presence of a w/o emulsifier at a temperature above the gel    point of the polymer solution,-   (b) cooling the dispersion while stirring to a temperature below the    gel point,-   (c) isolating the micro- and/or nanocapsules formed by decantation    and-   (d) adding an oil-absorbing auxiliary to the oily dispersion    obtained.

It has surprisingly been found that hydrophobicized powders can beproduced simply by mixing an oily dispersion of micro- and/ornanocapsules with oil-absorbing auxiliaries and that this formulationrepresents a stable powder with a high content of water-soluble activesubstances. The layer of the adhering oil-absorbing auxiliarieshydrophobicizes the hydrophilic micro- and/or nanocapsules and protectsthem against premature hydration and oxidation. The formulation is easyto incorporate in water-free preparations and is distinguished by highstorage stability without any agglomeration of the hydrophilic micro-and/or nanocapsules. In addition, the release of the encapsulated activesubstances can be controlled by varying the type and quantity of theoil-absorbing auxiliary.

The present invention also relates to a process for the production ofhydrophobicized powders consisting of micro- and/or nanocapsules, inwhich

-   (a) a heated aqueous solution of at least one polymer is dispersed    in an oil in the presence of a w/o emulsifier at a temperature above    the gel point of the polymer solution,-   (b) the dispersion is cooled while stirring to a temperature below    the gel point,-   (c) the micro- and/or nanocapsules formed are isolated by    decantation and-   (d) an oil-absorbing auxiliary is added to the oily dispersion    obtained,    and to the use of the hydrophobicized powders in cosmetic and/or    pharmaceutical preparations and detergents.    Micro- and/or Nanocapsules

The micro- and/or nanocapsules present in the hydrophobicized powdersaccording to the invention are formed during the cooling of apolymer-containing w/o emulsion. After decantation, the oily dispersionpresent after cooling has a solids content of 85 to 95% by weightconsisting of hydrophilic micro- and/or nanocapsules and 5 to 15% byweight of the oil used in the outer phase. The micro- and/ornanocapsules have a mean diameter of 0.1 to 500 μm, preferably 25 to 100μm and more particularly 10 to 50 μm. Particles smaller than 50 μm indiameter in particular resemble the particle size of many powderformulations in decorative cosmetics and may therefore beinconspicuously incorporated.

Polymers

Hydrophilic materials are mainly used as polymers for forming thecapsule matrix. The membrane may consist of natural, semisynthetic orsynthetic materials. Natural membrane materials are, for example, gumarabic, agar agar, agarose, carrageen, maltodextrins, alginic acid andsalts thereof, for example sodium or calcium alginate, fats and fattyacids, cetyl alcohol, collagen, chitosan, lecithins, gelatin, gluten,albumin, shellac, polysaccharides, such as starch or dextran,polypeptides, protein hydrolyzates, sucrose, xanthan or gellan gum.Semisynthetic membrane materials are inter alia chemically modifiedcelluloses, more particularly cellulose esters and ethers, for examplecellulose acetate, ethyl cellulose, hydroxypropyl cellulose,hydroxypropyl methyl cellulose and phthalate, methyl cellulose andcarboxymethyl cellulose, and starch derivatives, more particularlystarch ethers and esters, and stearates. Synthetic membrane materialsare, for example, polymers, such as polyacrylates, polyamides, polyvinylalcohol, polyglycolates, polyoxyethylenes, polylactates, polyglutamates,polyimides or polyvinyl pyrrolidone.

Oil Components

Oil components suitable for use as the outer phase in the production ofthe micro- and/or nanocapsules include vegetable, animal, semisyntheticand synthetic oils, for example Guerbet alcohols based on fatty alcoholscontaining 6 to 18 and preferably 8 to 10 carbon atoms, esters of linearC₆₋₂₂ fatty acids with linear C₆₋₂₂ fatty alcohols, esters of branchedC₆₋₁₃ carboxylic acids with linear C₆₋₂₂ fatty alcohols such as, forexample, myristyl myristate, myristyl palmitate, myristyl stearate,myristyl isostearate, myristyl oleate, myristyl behenate, myristylerucate, cetyl myristate, cetyl palmitate, cetyl stearate, cetylisostearate, cetyl oleate, cetyl behenate, cetyl erucate, stearylmyristate, stearyl palmitate, stearyl stearate, stearyl isostearate,stearyl oleate, stearyl behenate, stearyl erucate, isostearyl myristate,isostearyl palmitate, isostearyl stearate, isostearyl isostearate,isostearyl oleate, isostearyl behenate, isostearyl oleate, oleylmyristate, oleyl palmitate, oleyl stearate, oleyl isostearate, oleyloleate, oleyl behenate, oleyl erucate, behenyl myristate, behenylpalmitate, behenyl stearate, behenyl isostearate, behenyl oleate,behenyl behenate, behenyl erucate, erucyl myristate, erucyl palmitate,erucyl stearate, erucyl isostearate, erucyl oleate, erucyl behenate anderucyl erucate. Also suitable are esters of linear C₆₋₂₂ fatty acidswith branched alcohols, more particularly 2-ethyl hexanol, esters ofhydroxycarboxylic acids with linear or branched C₆₋₂₂ fatty alcohols,more especially Dioctyl Malate, esters of linear and/or branched fattyacids with polyhydric alcohols (for example propylene glycol, dimer diolor trimer triol) and/or Guerbet alcohols, triglycerides based on C₆₋₁₀fatty acids, liquid mono-/di-/triglyceride mixtures based on C₆₋₁₈ fattyacids, esters of C₆₋₂₂ fatty alcohols and/or Guerbet alcohols witharomatic carboxylic acids, more particularly benzoic acid, esters ofC₂₋₁₂ dicarboxylic acids with linear or branched alcohols containing 1to 22 carbon atoms or polyols containing 2 to 10 carbon atoms and 2 to 6hydroxyl groups, vegetable oils, branched primary alcohols, substitutedcyclohexanes, linear and branched C₆₋₂₂ fatty alcohol carbonates,Guerbet carbonates, esters of benzoic acid with linear and/or branchedC₆₋₂₂ alcohols (for example Finsolv® TN), linear or branched,symmetrical or nonsymmetrical dialkyl ethers containing 6 to 22 carbonatoms per alkyl group, ring opening products of epoxidized fatty acidesters with polyols, silicone oils and/or aliphatic or naphthenichydrocarbons such as, for example, squalane, squalene or dialkylcyclohexanes.

Oil Absorbers

The oil-absorbing auxiliary d) is used in quantities of 5 to 35% byweight, preferably in quantities of 10 to 30% by weight and moreparticularly in quantities of 15 to 25% by weight, based on the quantityof hydrophobicized powder. It may be selected from any cosmetically andpharmaceutically compatible substances such as, for example, organic andinorganic pigments, dimethicone, dimethicone cross polymers, starch,methacrylate compounds and acrylate copolymers, polymethylmethacrylates, silicates, magnesium stearate, zinc stearate, magnesiumcarbonate.

Active Substances for Cosmetic and Pharmaceutical Applications

Typical examples of active substances used in cosmetic andpharmaceutical preparations are plant extracts, active substances withantibacetrial, anti-acne and keratolytic properties, surfactants,cosmetic oils, pearlizing waxes, stabilizers, biogenic agents, vitamins,deodorants, antiperspirants, anti-dandruff agents, UV protectionfactors, antioxidants, preservatives, insect repellents, self-tanningagents, tyrosine inhibitors (depigmenting agents), perfume oils anddyes.

Anionic, nonionic, cationic and/or amphoteric or zwitterionicsurfactants may be encapsulated as surfactants. Typical examples ofanionic surfactants are soaps, alkyl benzenesulfonates,alkanesulfonates, olefin sulfonates, alkylether sulfonates, glycerolether sulfonates, α-methyl ester sulfonates, sulfofatty acids, alkylsulfates, fatty alcohol ether sulfates, glycerol ether sulfates, fattyacid ether sulfates, hydroxy mixed ether sulfates, monolyceride (ether)sulfates, fatty acid amide (ether) sulfates, mono- and dialkylsulfosuccinates, mono- and dialkyl sulfosuccinamates,sulfotriglycerides, amide soaps, ether carboxylic acids and saltsthereof, fatty acid isethionates, fatty acid sarcosinates, fatty acidtaurides, N-acylamino acids such as, for example, acyl lactylates, acyltartrates, acyl glutamates and acyl aspartates, alkyl oligoglucosidesulfates, protein fatty acid condensates (particularly wheat-basedvegetable products) and alkyl-(ether) phosphates. If the anionicsurfactants contain polyglycol ether chains, they may have aconventional homolog distribution although they preferably have anarrow-range homolog distribution. Typical examples of nonionicsurfactants are fatty alcohol polyglycol ethers, alkylphenol polyglycolethers, fatty acid polyglycol esters, fatty acid amide polyglycolethers, fatty amine polyglycol ethers, alkoxylated triglycerides, mixedethers and mixed formals, optionally partly oxidized alk(en)yloligoglycosides or glucuronic acid derivatives, fatty acid-N-alkylglucamides, protein hydrolyzates (particularly wheat-based vegetableproducts), polyol fatty acid esters, sugar esters, sorbitan esters,polysorbates and amine oxides. If the nonionic surfactants containpolyglycol ether chains, they may have a conventional homologdistribution, although they preferably have a narrow-range homologdistribution. Typical examples of cationic surfactants are quaternaryammonium compounds, for example dimethyl distearyl ammonium chloride,and esterquats, more particularly quaternized fatty acid trialkanolamineester salts. Typical examples of amphoteric or zwitterionic surfactantsare alkylbetaines, alkylamidobetaines, aminopropionates,aminoglycinates, imidazolinium betaines and sulfobetaines. Thesurfactants mentioned are all known compounds. Information on theirstructure and production can be found in relevant synoptic works, cf.for example J. Falbe (ed.), “Surfactants in Consumer Products”, SpringerVerlag, Berlin, 1987, pages 54 to 124 or J. Falbe (ed.), “Katalysatoren,Tenside und Mineral-öladditive (Catalysts, Surfactants and Mineral OilAdditives)”, Thieme Verlag, Stuttgart, 1978, pages 123–217.

Suitable pearlizing waxes are, for example, alkylene glycol esters,especially ethylene glycol distearate; fatty acid alkanolamides,especially cocofatty acid diethanolamide; partial glycerides, especiallystearic acid monoglyceride; esters of polybasic, optionallyhydroxysubstituted carboxylic acids with fatty alcohols containing 6 to22 carbon atoms, especially long-chain esters of tartaric acid; fattycompounds, such as for example fatty alcohols, fatty ketones, fattyaldehydes, fatty ethers and fatty carbonates which contain in all atleast 24 carbon atoms, especially laurone and distearylether; fattyacids, such as stearic acid, hydroxystearic acid or behenic acid, ringopening products of olefin epoxides containing 12 to 22 carbon atomswith fatty alcohols containing 12 to 22 carbon atoms and/or polyolscontaining 2 to 15 carbon atoms and 2 to 10 hydroxyl groups and mixturesthereof.

Metal salts of fatty acids such as, for example, magnesium, aluminiumand/or zinc stearate or ricinoleate may be used as stabilizers.

In the context of the invention, biogenic agents are, for example,tocopherol, tocopherol acetate, tocopherol palmitate, ascorbic acid,deoxyribonucleic acid, retinol, bisabolol, allantoin, phytantriol,panthenol, AHA acids, koji acid, amino acids, ceramides,pseudoceramides, essential oils, plant extracts and vitamin complexes.

Cosmetic deodorants counteract, mask or eliminate body odors. Body odorsare formed through the action of skin bacteria on apocrine perspirationwhich results in the formation of unpleasant-smelling degradationproducts. Accordingly, deodorants contain active principles which act asgerm inhibitors, enzyme inhibitors, odor absorbers or odor maskers.

Basically, suitable germ inhibitors are any substances which act againstgram-positive bacteria such as, for example, 4-hydroxybenzoic acid andsalts and esters thereof,N-(4-chlorophenyl)-N′-(3,4-dichlorophenyl)-urea,2,4,4′-trichloro-2′-hydroxydiphenylether (triclosan),4-chloro-3,5-dimethylphenol,2,2′-methylene-bis-(6-bromo-4-chlorophenol),3-methyl-4-(1-methylethyl)-phenol, 2-benzyl-4-chlorophenol,3-(4-chlorophenoxy)-propane-1,2-diol, 3-iodo-2-propinyl butyl carbamate,chlorhexidine, 3,4,4′-trichlorocarbanilide (TTC), antibacterialperfumes, thymol, thyme oil, eugenol, clove oil, menthol, mint oil,farnesol, phenoxyethanol, glycerol monolaurate (GML), diglycerolmonocaprate (DMC), salicylic acid-N-alkylamides such as, for example,salicylic acid-n-octyl amide or salicylic acid-n-decyl amide.

Suitable enzyme inhibitors are, for example, esterase inhibitors.Esterase inhibitors are preferably trialkyl citrates, such as trimethylcitrate, tripropyl citrate, triisopropyl citrate, tributyl citrate and,in particular, triethyl citrate (Hydagen® CAT, Henkel KGaA, Düsseldorf,FRG). Esterase inhibitors inhibit enzyme activity and thus reduce odorformation. Other esterase inhibitors are sterol sulfates or phosphatessuch as, for example, lanosterol, cholesterol, campesterol, stigmasteroland sitosterol sulfate or phosphate, dicarboxylic acids and estersthereof, for example glutaric acid, glutaric acid monoethyl ester,glutaric acid diethyl ester, adipic acid, adipic acid monoethyl ester,adipic acid diethyl ester, malonic acid and malonic acid diethyl ester,hydroxycarboxylic acids and esters thereof, for example citric acid,malic acid, tartaric acid or tartaric acid diethyl ester, and zincglycinate.

Suitable odor absorbers are substances which are capable of absorbingand largely retaining the odor-forming compounds. They reduce thepartial pressure of the individual components and thus also reduce therate at which they spread. An important requirement in this regard isthat perfumes must remain unimpaired. Odor absorbers are not activeagainst bacteria. They contain, for example, a complex zinc salt ofricinoleic acid or special perfumes of largely neutral odor known to theexpert as “fixateurs” such as, for example, extracts of ladanum orstyrax or certain abietic acid derivatives as their principal component.Odor maskers are perfumes or perfume oils which, besides theirodor-masking function, impart their particular perfume note to thedeodorants. Suitable perfume oils are, for example, mixtures of naturaland synthetic perfumes. Natural perfumes include the extracts ofblossoms, stems and leaves, fruits, fruit peel, roots, woods, herbs andgrasses, needles and branches, resins and balsams. Animal raw materials,for example civet and beaver, may also be used. Typical syntheticperfume compounds are products of the ester, ether, aldehyde, ketone,alcohol and hydrocarbon type. Examples of perfume compounds of the estertype are benzyl acetate, p-tert.butyl cyclohexylacetate, linalylacetate, phenyl ethyl acetate, linalyl benzoate, benzyl formate, allylcyclohexyl propionate, styrallyl propionate and benzyl salicylate.Ethers include, for example, benzyl ethyl ether while aldehydes include,for example, the linear alkanals containing 8 to 18 carbon atoms,citral, citronellal, citronellyloxyacetaldehyde, cyclamen aldehyde,hydroxycitronellal, lilial and bourgeonal. Examples of suitable ketonesare the ionones and methyl cedryl ketone. Suitable alcohols are anethol,citronellol, eugenol, isoeugenol, geraniol, linalool, phenylethylalcohol and terpineol. The hydrocarbons mainly include the terpenes andbalsams. However, it is preferred to use mixtures of different perfumecompounds which, together, produce an agreeable fragrance. Othersuitable perfume oils are essential oils of relatively low volatilitywhich are mostly used as aroma components. Examples are sage oil,camomile oil, clove oil, melissa oil, mint oil, cinnamon leaf oil,lime-blossom oil, juniper berry oil, vetiver oil, olibanum oil, galbanumoil, ladanum oil and lavendin oil. The following are preferably usedeither individually or in the form of mixtures: bergamot oil,dihydromyrcenol, lilial, lyral, citronellol, phenylethyl alcohol,α-hexylcinnamaldehyde, geraniol, benzyl acetone, cyclamen aldehyde,linalool, Boisambrene Forte, Ambroxan, indole, hedione, sandelice,citrus oil, mandarin oil, orange oil, allylamyl glycolate, cyclovertal,lavendin oil, clary oil, β-damascone, geranium oil bourbon, cyclohexylsalicylate, Vertofix Coeur, Iso-E-Super, Fixolide NP, evernyl, iraldeingamma, phenylacetic acid, geranyl acetate, benzyl acetate, rose oxide,romilat, irotyl and floramat.

Antiperspirants reduce perspiration and thus counteract underarm wetnessand body odor by influencing the activity of the eccrine sweat glands.Aqueous or water-free antiperspirant formulations typically contain thefollowing ingredients:

-   astringent active principles,-   oil components,-   nonionic emulsifiers,-   co-emulsifiers,-   consistency factors,-   auxiliaries in the form of, for example, thickeners or complexing    agents and/or-   nonaqueous solvents such as, for example, ethanol, propylene glycol    and/or glycerol.

Suitable astringent active principles of antiperspirants are, above all,salts of aluminium, zirconium or zinc. Suitable antihydrotic agents ofthis type are, for example, aluminium chloride, aluminium chlorohydrate,aluminium dichlorohydrate, aluminium sesquichlorohydrate and complexcompounds thereof, for example with 1,2-propylene glycol, aluminiumhydroxyallantoinate, aluminium chloride tartrate, aluminium zirconiumtrichlorohydrate, aluminium zirconium tetrachlorohydrate, aluminiumzirconium pentachlorohydrate and complex compounds thereof, for examplewith amino acids, such as glycine. Oil-soluble and water-solubleauxiliaries typically encountered in antiperspirants may also be presentin relatively small amounts. Oil-soluble auxiliaries such as theseinclude, for example,

-   inflammation-inhibiting, skin-protecting or pleasant-smelling    essential oils,-   synthetic skin-protecting agents and/or-   oil-soluble perfume oils.

Typical water-soluble additives are, for example, preservatives,water-soluble perfumes, pH adjusters, for example buffer mixtures,water-soluble thickeners, for example water-soluble natural or syntheticpolymers such as, for example, xanthan gum, hydroxyethyl cellulose,polyvinyl pyrrolidone or high molecular weight polyethylene oxides.

Suitable antidandruff agents are climbazol, octopirox, ketoconazole andzinc pyrithione.

Examples of UV protection factors are organic substances (light filters)which are liquid or crystalline at room temperature and which arecapable of absorbing ultraviolet radiation and of releasing the energyabsorbed in the form of longer-wave radiation, for example heat. UV-Bfilters can be oil-soluble or water-soluble. The following are examplesof oil-soluble substances:

-   3-benzylidene camphor or 3-benzylidene norcamphor and derivatives    thereof, for example 3-(4-methylbenzylidene)-camphor, as described    in EP 0693471 B1;-   4-aminobenzoic acid derivatives, preferably    4-(dimethylamino)-benzoic acid-2-ethylhexyl ester,    4-(dimethylamino)-benzoic acid-2-octyl ester and    4-(dimethylamino)-benzoic acid amyl ester;-   esters of cinnamic acid, preferably 4-methoxycinnamic    acid-2-ethylhexyl ester, 4-methoxycinnamic acid propyl ester,    4-methoxycinnamic acid isoamyl ester, 2-cyano-3,3-phenylcinnamic    acid-2-ethylhexyl ester (Octocrylene);-   esters of salicylic acid, preferably salicylic acid-2-ethylhexyl    ester, salicylic acid-4-isopropylbenzyl ester, salicylic acid    homomenthyl ester;-   derivatives of benzophenone, preferably    2-hydroxy-4-methoxybenzophenone,    2-hydroxy-4-methoxy-4′-methylbenzophenone,    2,2′-dihydroxy-4-methoxybenzophenone;-   esters of benzalmalonic acid, preferably 4-methoxybenzalmalonic acid    di-2-ethylhexyl ester;-   triazine derivatives such as, for example,    2,4,6-trianilino-(p-carbo-2′-ethyl-1′-hexyloxy)-1,3,5-triazine and    Octyl Triazone, as described in EP 0 818 450 A1, or Dioctyl Butamido    Triazine (Uvasorb® HEB);-   propane-1,3-diones such as, for example,    1-(4-tert.butylphenyl)-3-(4′-methoxyphenyl)-propane-1,3-dione;-   ketotricyclo(5.2.1)decane derivatives, as described in EP 0 694 521    B1.

Suitable water-soluble substances are

-   2-phenylbenzimidazole-5-sulfonic acid and alkali metal, alkaline    earth metal, ammonium, alkylammonium, alkanolammonium and    glucammonium salts thereof;-   sulfonic acid derivatives of benzophenones, preferably    2-hydroxy-4-methoxybenzophenone-5-sulfonic acid and salts thereof;-   sulfonic acid derivatives of 3-benzylidene camphor such as, for    example, 4-(2-oxo-3-bornylidenemethyl)-benzene sulfonic acid and    2-methyl-5-(2-oxo-3-bornylidene)-sulfonic acid and salts thereof.

Typical UV-A filters are, in particular, derivatives of benzoyl methanesuch as, for example1-(4′-tert.butylphenyl)-3-(4′-methoxyphenyl)-propane-1,3-dione,4-tert-butyl-4′-methoxydibenzoylmethane (Parsol 1789),1-phenyl-3-(4′-isopropylphenyl)-propane-1,3-dione and the eneaminecompounds described in DE 19712033 A1 (BASF). The UV-A and UV-B filtersmay of course also be used in the form of mixtures. Besides the solublesubstances mentioned, insoluble pigments, i.e. finely dispersed metaloxides or salts, may also be used for this purpose. Examples of suitablemetal oxides are, in particular, zinc oxide and titanium dioxide andalso oxides of iron, zirconium, silicon, manganese, aluminium and ceriumand mixtures thereof. Silicates (talcum), barium sulfate and zincstearate may be used as salts. The oxides and salts are used in the formof the pigments for skin-care and skin-protecting emulsions anddecorative cosmetics. The particles should have an average diameter ofless than 100 nm, preferably from 5 to 50 nm and more preferably from 15to 30 nm. They may be spherical in shape although ellipsoidal particlesor other non-spherical particles may also be used. The pigments may alsobe surface-treated, i.e. hydrophilicized or hydrophobicized. Typicalexamples are coated titanium dioxides such as, for example, TitandioxidT 805 (Degussa) or Eusolex® T2000 (Merck). Suitable hydrophobic coatingmaterials are, above all, silicones and particularly trialkoxyoctylsilanes or simethicones. So-called micro- or nanopigments are preferablyused in sun protection products. Micronized zinc oxide is preferablyused. Other suitable UV filters can be found in P. Finkel's review inSÖFW-Journal 122, 543 (1996).

Besides the two above-mentioned groups of primary protection factors,secondary protection factors of the antioxidant type may also be used.Secondary sun protection factors of the antioxidant type interrupt thephotochemical reaction chain which is initiated when UV rays penetrateinto the skin. Typical examples of suitable antioxidants are amino acids(for example glycine, histidine, tyrosine, tryptophane) and derivativesthereof, imidazoles (for example urocanic acid) and derivatives thereof,peptides, such as D,L-carnosine, D-carnosine, L-carnosine andderivatives thereof (for example anserine), carotinoids, carotenes (forexample α-carotene, β-carotene, lycopene) and derivatives thereof,chlorogenic acid and derivatives thereof, liponic acid and derivativesthereof (for example dihydroliponic acid), aurothioglucose,propylthiouracil and other thiols (for example thioredoxine,glutathione, cysteine, cystine, cystamine and glycosyl, N-acetyl,methyl, ethyl, propyl, amyl, butyl and lauryl, palmitoyl, oleyl,γ-linoleyl, cholesteryl and glyceryl esters thereof) and their salts,dilaurylthiodipropionate, distearylthiodipropionate, thiodipropionicacid and derivatives thereof (esters, ethers, peptides, lipids,nucleotides, nucleosides and salts) and sulfoximine compounds (forexample butionine sulfoximines, homocysteine sulfoximine, butioninesulfones, penta-, hexa- and hepta-thionine sulfoximine) in very smallcompatible dosages (for example pmol to μmol/kg), also (metal) chelators(for example α-hydroxyfatty acids, palmitic acid, phytic acid,lactoferrine), α-hydroxy acids (for example citric acid, lactic acid,malic acid), humic acid, bile acid, bile extracts, bilirubin,biliverdin, EDTA, EGTA and derivatives thereof, unsaturated fatty acidsand derivatives thereof (for example γ-linolenic acid, linoleic acid,oleic acid), folic acid and derivatives thereof, ubiquinone andubiquinol and derivatives thereof, vitamin C and derivatives thereof(for example ascorbyl palmitate, Mg ascorbyl phosphate, ascorbylacetate), liponic acid, tocopherols and derivatives (for example vitaminE acetate), vitamin A and derivatives (vitamin A palmitate) andconiferyl benzoate of benzoin resin, rutinic acid and derivativesthereof, α-glycosyl rutin, ferulic acid, furfurylidene glucitol,carnosine, butyl hydroxytoluene, butyl hydroxyanisole, nordihydroguaiacresin acid, nordihydroguaiaretic acid, trihydroxybutyrophenone, uricacid and derivatives thereof, mannose and derivatives thereof,Superoxid-Dismutase, zinc and derivatives thereof (for example ZnO,ZnSO₄), selenium and derivatives thereof (for example seleniummethionine), stilbenes and derivatives thereof (for example stilbeneoxide, trans-stilbene oxide) and derivatives of these active principlessuitable for the purposes of the invention (salts, esters, ethers,sugars, nucleotides, nucleosides, peptides and lipids).

Suitable preservatives are, for example, phenoxyethanol, formaldehydesolution, parabens, pentanediol or sorbic acid and the other classes ofcompounds listed in Appendix 6, Parts A and B of the Kosmetikverordnung(“Cosmetics Directive”). Suitable insect repellents areN,N-diethyl-m-toluamide, pentane-1,2-diol or EthylButylacetyl-aminopropionate. A suitable self-tanning agent isdihydroxyacetone. Tyrosine inhibitors, which prevent the formation ofmelanin and are used in depigmenting formulations, are for examplearbutin, koji acid, coumaric acid and ascorbic acid (vitamin C)

Suitable perfume oils are mixtures of natural and synthetic perfumes.Natural perfumes include the extracts of blossoms (lily, lavender, rose,jasmine, neroli, ylang-ylang), stems and leaves (geranium, patchouli,petitgrain), fruits (anise, coriander, caraway, juniper), fruit peel(bergamot, lemon, orange), roots (nutmeg, angelica, celery, cardamon,costus, iris, calmus), woods (pinewood, sandalwood, guaiac wood,cedarwood, rosewood), herbs and grasses (tarragon, lemon grass, sage,thyme), needles and branches (spruce, fir, pine, dwarf pine), resins andbalsams (galbanum, elemi, benzoin, myrrh, olibanum, opoponax). Animalraw materials, for example civet and beaver, may also be used. Typicalsynthetic perfume compounds are products of the ester, ether, aldehyde,ketone, alcohol and hydrocarbon type. Examples of perfume compounds ofthe ester type are benzyl acetate, phenoxyethyl isobutyrate,p-tert.butyl cyclohexylacetate, linalyl acetate, dimethyl benzylcarbinyl acetate, phenyl ethyl acetate, linalyl benzoate, benzylformate, ethylmethyl phenyl glycinate, allyl cyclohexyl propionate,styrallyl propionate and benzyl salicylate. Ethers include, for example,benzyl ethyl ether while aldehydes include, for example, the linearalkanals containing 8 to 18 carbon atoms, citral, citronellal,citronellyloxyacetaldehyde, cyclamen aldehyde, hydroxycitronellal,lilial and bourgeonal. Examples of suitable ketones are the ionones,α-isomethylionone and methyl cedryl ketone. Suitable alcohols areanethol, citronellol, eugenol, isoeugenol, geraniol, linalool,phenylethyl alcohol and terpineol. The hydrocarbons mainly include theterpenes and balsams. However, it is preferred to use mixtures ofdifferent perfume compounds which, together, produce an agreeablefragrance. Other suitable perfume oils are essential oils of relativelylow volatility which are mostly used as aroma components. Examples aresage oil, camomile oil, clove oil, melissa oil, mint oil, cinnamon leafoil, lime-blossom oil, juniper berry oil, vetiver oil, olibanum oil,galbanum oil, ladanum oil and lavendin oil. The following are preferablyused either individually or in the form of mixtures: bergamot oil,dihydromyrcenol, lilial, lyral, citronellol, phenylethyl alcohol,α-hexylcinnamaldehyde, geraniol, benzyl acetone, cyclamen aldehyde,linalool, Boisambrene Forte, Ambroxan, indole, hedione, sandelice,citrus oil, mandarin oil, orange oil, allylamyl glycolate, cyclovertal,lavendin oil, clary oil, β-damascone, geranium oil bourbon, cyclohexylsalicylate, Vertofix Coeur, Iso-E-Super, Fixolide NP, evernyl, iraldeingamma, phenylacetic acid, geranyl acetate, benzyl acetate, rose oxide,romillat, irotyl and floramat.

Suitable dyes are any of the substances suitable and approved forcosmetic purposes as listed, for example, in the publication“Kosmetische Färbemittel” of the Farbstoffkommission der DeutschenForschungs-gemeinschaft, Verlag Chemie, Weinheim, 1984, pages 81 to 106.These active principles may also be present in the capsules solely foraesthetic reasons, i.e are not intended for controlled release.

Active Principles for Detergent Applications

Where microcapsules are used in the field of detergents, particularlylaundry detergents, it is again desirable to prevent the variousingredients from coming into contact with one another. Thus, it isappropriate to encapsulate chemically sensitive substances, such asperfume oils or optical brighteners for example, in order to safeguardtheir activity, for example in chlorine or peroxide bleach liquors, evenin the event of prolonged storage. However, use is also made of the factthat the bleaching of textiles generally takes place during rather thanat the beginning of the washing process, the release delayed bymechanical action on the microcapsules ensuring that the bleachingagents develop their full effect at the right time. Accordingly, activeprinciples to be encapsulated for detergent applications include, aboveall, bleaching agents, bleach activators, enzymes, redepositioninhibitors, optical brighteners and (chlorine- and peroxide-stable)perfumes and dyes.

Among the compounds yielding hydrogen peroxide in water which are usedas bleaching agents, sodium perborate tetrahydrate and sodium perboratemonohydrate are particularly important. Other suitable bleaching agentsare, for example, peroxycarbonate, citrate perhydrates and salts ofperacids, such as perbenzoates, peroxyphthalates ordiperoxydodecanedioic acid. They are normally used in quantities of 8 to25% by weight. Sodium perborate monohydrate is preferred and is used inquantities of 10 to 20% by weight and preferably in quantities of 10 to15% by weight. By virtue of its ability to bind free water to form thetetrahydrate, it contributes towards increasing the stability of thedetergent.

Examples of suitable bleach activators are N-acyl and O-acyl compoundswhich form organic peracids with hydrogen peroxide, preferablyN,N′-tetraacylated diamines, also carboxylic anhydrides and esters ofpolyols, such as glucose pentaacetate. The bleach activator content ofbleach-containing compositions is in the usual range, i.e. preferablybetween 1 and 10% by weight and more preferably between 3 and 8% byweight. Particularly preferred bleach activators areN,N,N′,N′-tetraacetyl ethylenediamine and1,5-diacetyl-2,4-dioxohexahydro-1,3,5-triazine.

Suitable enzymes are those from the class of proteases, lipases,amylases, cellulases and mixtures thereof. Enzymes obtained frombacterial strains or fungi, such as Bacillus subtilis, Bacilluslicheniformis and Streptomyces griseus, are particularly suitable.Proteases of the subtilisin type are preferably used, proteases obtainedfrom Bacillus lentus being particularly preferred. They may be used inquantities of about 0.2 to about 2% by weight. The enzymes may beadsorbed onto supports and/or encapsulated in membrane materials toprotect them against premature decomposition. In addition to themonohydric and polyhydric alcohols and the phosphonates, thecompositions may contain other enzyme stabilizers. For example, 0.5 to1% by weight of sodium formate may be used. It is also possible to useproteases which are stabilized with soluble calcium salts and which havea calcium content of preferably about 1.2% by weight, based on theenzyme. However, it is of particular advantage to use boron compounds,for example boric acid, boron oxide, borax and other alkali metalborates, such as the salts of orthoboric acid (H₃BO₃), metaboric acid(HBO₂) and pyroboric acid (tetraboric acid H₂B₄O₇).

Suitable redeposition inhibitors are water-soluble, generally organiccolloids, for example the water-soluble salts of polymeric carboxylicacids, glue, gelatine, salts of ether carboxylic acids or ether sulfonicacids of starch or cellulose or salts of acidic sulfuric acid esters ofcellulose or starch. Water-soluble polyamides containing acidic groupsare also suitable for this purpose. Soluble starch preparations andother starch products than those mentioned above, for example degradedstarch, aldehyde starches, etc., may also be used. Polyvinyl pyrrolidoneis also suitable. However, cellulose ethers, such as carboxymethylcellulose, methyl cellulose, hydroxyalkyl cellulose, and mixed ethers,such as methyl hydroxyethyl cellulose, methyl hydroxypropyl cellulose,methyl carboxymethyl cellulose and mixtures thereof, and polyvinylpyrrolidone are also preferably used, for example in quantities of 0.1to 99% by weight and preferably 1 to 5% by weight, based on thecomposition.

Derivatives of diaminostilbene disulfonic acid or alkali metal saltsthereof may be used as optical brighteners. Suitable optical brightenersare, for example, salts of4,4′-bis-(2-anilino-4-morpholino-1,3,5-triazinyl-6-amino)-stilbene-2,2′-disulfonicacid or compounds of similar structure which, instead of the morpholinogroup, contain a diethanolamino group, a methylamino group, an anilinogroup or a 2-methoxyethylamino group. Brighteners of the substituteddiphenyl styryl type, for example alkali metal salts of4,4′-bis-(2-sulfostyryl)-diphenyl,4,4′-bis-(4-chloro-3-sulfostyryl)-diphenyl or4-(4-chlorostyryl)-4′-(2-sulfostyryl)-diphenyl, may also be present.Mixtures of the brighteners mentioned above may also be used. Aparticularly preferred dye is Tinolux® (a product of Ciba-Geigy).

Examples of perfumes stable to active chlorine are: citronellol(3,7-dimethyl-6-octen-1-ol), dimethyl octanol (3,7-dimethyl-1-octanol),hydroxycitronellol (3,7-dimethyloctane-1,7-diol), mugol(3,7-dimethyl-4,6-octatrien-3-ol), myrcenol(2-methyl-6-methylene-7-octen-2-ol), terpinolene(p-mentho-1,4-(8)-diene), ethyl-2-methyl butyrate, phenyl propylalcohol, galaxolide (1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexamethylcyclopental-2-benzopyran), tonalide (7-acetyl-1,1,3,4,4,6-hexamethyltetrahydronaphthalene), rose oxide, linalol oxide,2,6-dimethyl-3-octanol, tetrahydroethyl linalool, tetrahydroethyllinalyl acetate, o-sec.-butyl cyclohexyl acetate and isolonediphorenepoxide and also isoborneal, dihydroterpineol, isobornylacetate, dihydroterpenyl acetate). Other suitable perfumes are thesubstances mentioned columns 3 and 4 of European patent application EP0622451 A1 (Procter & Gamble).

Besides inorganic types, such as iron or bismuth oxides for example,suitable pigments are, above all, green chlorophthalocyanines (Pigmosol®Grün, Hostaphine® Grün), yellow Solar Yellow BG 300 (Sandoz), bluechlorophthalocyanine (Hostaphine® Blau) or Cosmenyl® Blau.

Chitosans

Chitosans are biopolymers which belong to the group of hydrocolloids.Chemically, they are partly deacetylated chitins differing in theirmolecular weights which contain the following—idealized—monomer unit:

In contrast to most hydrocolloids, which are negatively charged atbiological pH values, chitosans are cationic biopolymers under theseconditions. The positively charged chitosans are capable of interactingwith oppositely charged surfaces and are therefore used in cosmetichair-care and body-care products and pharmaceutical preparations (cf.Ullmann's Encyclopedia of Industrial Chemistry, 5th Ed., Vol. A6,Weinheim, Verlag Chemie, 1986, pages 231–332). Overviews of this subjecthave also been published, for example, by B. Gesslein et al. in HAPPI27, 57 (1990), O. Skaugrud in Drug Cosm. Ind. 148, 24 (1991) and E.Onsoyen et al. in Seifen-Öle-Fette-Wachse 117, 633 (1991). Chitosans areproduced from chitin, preferably from the shell residues of crustaceanswhich are available in large quantities as inexpensive raw materials. Ina process described for the first time by Hackmann et al., the chitin isnormally first deproteinized by addition of bases, deminerlized byaddition of mineral acids and, finally, deacetylated by addition ofstrong bases, the molecular weights being distributed over a broadspectrum. Corresponding processes are known, for example, from Makromol.Chem. 177, 3589 (1976) or French patent application FR 2701266 A.Preferred types are those which are disclosed in German patentapplications DE 4442987 A1 and DE 19537001 A1 (Henkel) and which have anaverage molecular weight of 10,000 to 500,000 dalton or 800,000 to1,200,000 dalton, a Brookfield viscosity (1% by weight in glycolic acid)below 5,000 mPas, a degree of deacetylation of 80 to 88% and an ashcontent of less than 0.3% by weight. In the interests of bettersolubility in water, the chitosans are generally used in the form oftheir salts, preferably as glycolates.Production of the Microcapsules

Basically, any processes for the production of micro- and/ornanocapsules in which the capsules formed are present as a dispersionwith an oil component in the outer phase, which may then be mixed withthe oil-absorbing auxiliary, may be used. Particular emphasis is placedon the w/o emulsion method combined with gelation by temperaturereduction.

To produce the hydrophobicized powders according to the invention, anaqueous solution or dispersion is initially prepared by thorough mixingof active substances and auxiliaries. The hydrophilic polymers used toform the matrix are dissolved in the solution or dispersion by heatingbeyond their gel point or, if necessary, are dissolved while heating inthe aqueous solvent and combined with the heated solution of the otheractive substances and auxiliaries. If necessary, other hydrophilicsolvents, for example ethanol or isopropanol, may also be added to theaqueous solution besides water. This aqueous solution or dispersion isthen dispersed with intensive stirring in an oil heated to beyond thegel temperature of the matrix-forming polymer. Up to this step, alloperations take place above the gel temperature of the hydrophilicpolymer. After homogeneous emulsification, the emulsion is cooled to atemperature below the gel point of the hydrophilic polymer, resulting inthe formation of an oily dispersion with a solids content of micro-and/or nanocapsules and an outer phase of the oil. To isolate the micro-and/or nanocapsules, excess oil is slowly decanted off so that the thedispersion obtained has an oil content of about 20 to 2% by weight andpreferably 10 to 5% by weight.

The adhering oil layer is then adsorbed by intensive mixing of thedispersion with an oil-absorbing powder-form auxiliary. Mixing iscarried out with commercially available powder mixers until ahomogeneous powder mixture is obtained.

On average, the micro- and/or nanocapsules present in the powder have adiameter of 0.1 to 500 μm, preferably 50 to 100 μm and more particularly10 to 50 μm. The particle diameter is determined by laser diffractometry(Malvern Instruments), the measurements giving a volume distribution.

In the encapsulation of active substances, the micro- and/ornanocapsules may be charged with 0.1 to 50% by weight, preferably 1 to25% by weight and more particularly 5 to 10% by weight of activesubstance.

Commercial Applications

Micro- and/or nanocapsules in the form of the hydrophobicized powder maybe used for various purposes. Their main function is the controlledreleased and protection of the encapsulated substances. This protectivefunction includes oxidation by atmospheric oxygen, the protection ofhygroscopic materials, UV protection and also the separation of mutuallyincompatible ingredients which can be separately stored in this way. Thestability of the processed ingredients in particular is thus increased.In addition, it may be intended to mask ingredients where odor, tasteand/or appearance are to be concealed.

Basically, the choice of the active substances encapsulated in the newmicrocapsules is not critical. Preferably, they are substances which areonly released by mechanical destruction of the microcapsules. In casessuch as these, the function of the microcapsules is to prevent contactbetween the surrounding environment and the active substance and hence achemical reaction or degradation. It may be that the substancesencapsulated in the capsules are not to be released at all and aremerely intended to give the preparation an aesthetic appearance. This isoften the case, for example, with dyes. It is of course clear that theseforms of use may also exist alongside one another. In particular, it ispossible, for example, to encapsulate a perfume for subsequent releasetogether with a pigment which gives the capsules a particularappearance.

For processing in cosmetic and/or pharmaceutical preparations, it isoften of advantage for the micro- and/or nanocapsules to be present inpowder form. The powder formulations according to the invention may becharged with various active principles which they are capable ofreleasing with delay and under mechanical pressure. They aredistinguished from known formulations by greater stability, particularlyin the event of further mechanical processing. Accordingly, thehydrophobicized powders may also be used in laundry detergents,dishwasher detergents, cleaners and conditioners and also for theproduction of foods. The powders may normally be used in quantities of0.01 to 100% by weight, preferably in quantities of 0.1 to 50% by weightand more preferably in quantities of 1 to 25% by weight, based on thepreparations. The powders according to the invention are preferably usedfor the production of cosmetic products such as, for example, hairshampoos, hair lotions, foam baths, shower baths, creams, gels, lotions,alcoholic and aqueous/alcoholic solutions, emulsions, wax/fat-basedcompositions, stick preparations, powders and, more particularly,decorative cosmetic preparations such as, for example, makeup, rouge,lipstick, cajal, eye shadow, mascara and nail varnish. Thehydrophobicized powders may be excellently incorporated in particular inwater-free preparations which contain less than 5% by weight, preferablyless than 3% by weight and more particularly less than 1% by weight ofwater. These preparations may contain as further auxiliaries andadditives mild surfactants, oil components, emulsifiers, superfattingagents, pearlizing waxes, consistency factors, thickeners, polymers,silicone compounds, fats, waxes, lecithins, phospholipids, stabilizers,biogenic agents, deodorants, antiperspirants, antidandruff agents, filmformers, swelling agents, UV protection factors, antioxidants,hydrotropes, preservatives, insect repellents, self-tanning agents,tyrosine inhibitors (depigmenting agents), solubilizers, perfume oils,dyes and the like. The majority of these substances are also potentialactive principles with which the microcapsules may be charged and havealready been described in detail in this chapter.

EXAMPLES Example 1

1a: Production of the hydrophilic particles % by weight Phase A 1 Agar * 1.50 2 Preservative q.s. 3 Titanium dioxide  3.00 4 Photonyl LS ® **30.00 5 Water to 100.0 Phase B 6 Cetiol ® OE Dicaprylyl Ether 99.50 7Dehymuls ® Polyglyceryl-2-Dipolyhydroxystearate 0.50 PGPH * GranulatedAgar-Agar produced by Merck, Darmstadt, Art. No.: 1.01614 ** Commercialproduct of Laboratoires SérobioIogiques consisting of arginine, sodiumadenosine triphosphate, mannitol, pyridoxine HCI, RNA, histidine HOI,phenylalanine and tyrosine

Agar is dissolved in preserved water at 90° C. and then cooled to 75° C.Titanium dioxide and Photonyl® LS are then added with stirring. thesolution is kept at 55° C. Cetiol® OE and Dehymuls® PGHG are mixed andheated to 40–42° C. One part of phase A is dispersed in 3.3 parts ofphase B by stirring with an Ultra-Turrax for 5 minutes at 40–42° C. Thedispersion is then cooled with stirring to room temperature (25° C.) sothat the drops of phase A harden to form microcapsules. Themicrocapsules are isolated by decantation. In view of the adhering oilphase, however, the formulation obtained consists of an oily dispersionwith a high solids content (phase A: 93% by weight, phase B: 7% byweight).

1b: Production of the hydrophobicized powder Constituents % by weight 8Microcapsule dispersion from 1a 75 9 Polytrap ® 6603* Acrylate copolymer25 * Manufacturer: Advanced Polymer Systems, marketing: Dow Corning

The oily microcapsule dispersion is then mixed with Polytrap® 6603 untila homogeneous powder is obtained. The content of Photonyl® LS in thehydrophobicized powder is 20% by weight.

1. A process for making hydrophobicized powders of micro- and/ornanocapsules comprising: (a) providing an aqueous polymer solutioncontaining at least one active ingredient and at least one hydrophilicpolymer; (b) providing an oil component heated to a temperature above agel point of the aqueous polymer solution; (c) dispersing (a) in (b) inthe presence of a water-in-oil emulsifier to form a dispersion; (d)cooling the dispersion while mixing to a temperature below the gel pointof the aqueous polymer solution to form micro- and/or nanocapsulescontaining the active ingredient encapsulated therein; (e) harvestingthe micro- and/or nanocapsules from the dispersion to recover micro-and/or nanocapsules coated with oil; and (f) contacting the micro-andlor nanocapsules coated with oil with an oil-absorbing auxiliaryingredient, whereby, micro- and/or nanocapsules with a protective,hydrophobic coating comprising the oil-absorbing auxiliary ingredient isformed.
 2. The process of claim 1 wherein the oil-absorbing auxiliaryingredient is employed in an amount of from about 5 to 35% by weight,based on the weight of the hydrophobicized powder.
 3. The process ofclaim 1 wherein the oil-absorbing auxiliary ingredient is employed in anamount of from about 15 to 25% by weight, based on the weight of thehydrophobicized powder.
 4. The process of claim 1 wherein the micro-and/or nanocapsules have a mean particle diameter of from about 0.1 to500 μm.
 5. The process of claim 1 wherein the process producesmicrocapsules having a mean particle diameter of from about 10 to 50 μm.6. The process of claim 1 wherein the micro- and/or nanocapsules areharvested from the dispersion by decanting the oil from the dispersionto form a decanted dispersion containing the micro- and/or nanocapsules.7. The process of claim 6 wherein the decanted dispersion has a residualoil content of from about 2 to 20% by weight, based on the weight of thedecanted dispersion.
 8. The process of claim 6 wherein the decanteddispersion has a residual oil content of from about 5 to 10% by weight,based on the weight of the decanted dispersion.
 9. The process of claim1 wherein the micro- and/or nanocapsules contain from about 0.1 to 50%by weight of active ingredient.
 10. The process of claim 1 wherein themicro- and/or nanocapsules contain from about 5 to 10% by weight ofactive ingredient.